fwiw
somewhat in relation to Eusebius's
Eccl. hist. 3.39.15, attributed to Papias, but also independently;
Irenaeus
Against Heresies III.1.1:
We have learned from none others the plan of our salvation, than from those through whom the Gospel has come down to us, which they did at one time proclaim in public, and, at a later period, by the will of God, handed down to us in the Scriptures, to be the ground and pillar of our faith. For it is unlawful to assert that they preached before they possessed perfect knowledge, as some do even venture to say, boasting themselves as improvers of the apostles.
For,
after our Lord rose from the dead, [the apostles] were invested with power from on high, when the Holy Spirit came down [upon them]
...and had perfect knowledge: they departed to the ends of the earth, preaching the glad tidings of the good things [sent] from God to us... the Gospel of God.
Matthew also issued a written Gospel among the Hebrews in their own dialect, while Peter and Paul were preaching at Rome, and laying the foundations of the Church. After their departure, Mark, the disciple and interpreter of Peter, did also hand down to us in writing what had been preached by Peter. Luke also, the companion of Paul, recorded in a book the Gospel preached by him. Afterwards, John, the disciple of the Lord, who also had leaned upon His breast, did himself publish a Gospel during his residence at Ephesus in Asia.
https://www.earlychristianwritings.com/ ... book3.html, and
https://www.newadvent.org/fathers/0103301.htm
cf. Eusebius
Eccl. hist. III.39.15:
"Mark, having become the interpreter of Peter, wrote down accurately, though not in order, whatsoever he remembered of the things said or done by Christ. For he neither heard the Lord nor followed him, but afterward, as I said, he followed Peter, who adapted his teaching to the needs of his hearers, but with no intention of giving a connected account of the Lord's discourses, so that Mark committed no error while he thus wrote some things as he remembered them. For he was careful of one thing, not to omit any of the things which he had heard, and not to state any of them falsely."